1. Field
This disclosure relates to multimode seeker systems for projectiles, missiles, and other ordinance that, in at least one mode, engage targets by detecting and following laser light reflected from the targets.
2. Description of the Related Art
Ordinance such as guided artillery projectiles, guided missiles, and guided bombs, all of which will be referred to herein as “projectiles”, may include a variety of imaging or non-imagining sensors to detect and track potential targets. Sensors used to guide projectiles to an intended target are commonly referred to as seekers. Seekers may operate in various portions of the electromagnetic spectrum, including the visible, infrared (IR), microwave, and millimeter wave (MMW) portions of the spectrum. Some projectiles may incorporate multiple sensors that operate in more than one portion of the spectrum. A seeker that incorporates multiple sensors that share a common aperture and/or common optical system is commonly called a multimode seeker.
One type of seeker used in projectiles is a semi-active laser (SAL) seeker to detect laser radiation reflected from an intended target and to provide signals indicative of the target bearing such that the projectile can be guided to the target. The SAL may include an optical system to capture and focus the reflected laser radiation and a detector. In order to provide high sensitivity, the SAL optical system may have a large aperture and high optical efficiency.
In order to guide a projectile to a target when laser illumination of the target is not available, the projectile may be equipped with a dual-mode seeker including a SAL seeker and an imaging infrared (IIR) seeker. The projectile may be equipped with a tri-mode seeker including a SAL seeker, an IIR seeker, and a millimeter-wave radar seeker.
Throughout this description, elements appearing in figures are assigned three-digit reference designators, where the most significant digit is the figure number and the two least significant digits are specific to the element. An element that is not described in conjunction with a figure may be presumed to have the same characteristics and function as a previously-described element having a reference designator with the same least significant digits.